[Docs] Update Travis CI part in README.md

Add test for `local` keyword in SC2154

Follow-up to koalaman/shellcheck#988

SC2029: Skip when there are options to ssh

Fixes #327

SC2029 generates false positives when given an ssh command that includes
options with arguments because it assumes the first non-option must be
the host:port argument and the last argument is a command to run.
As suggested the comments on #327, this change fixes those by skipping
the check when there are any options present.

This change adds a test case for a valid command that gets falsely
flagged with SC2029.

Use readVariableName combinator

Add snapcraft.yaml to build snap package

Update openSUSE instruction

Package is main repo of all versions. No need to add repository.

Extend SC2216/SC2217 with 'true' and 'false'

convert http:// URIs to https://

Also update the ShellCheck homepage to the new dedicated domain.

This release is dedicated to net neutrality. Remember when the Internet
was a meritocracy? [Please drink a verification can to continue.]

Fix isClosingFileOp (fixes issue #862)